At 21.55 hours on 30 April 1941 the unescorted Lassell (Master Alfred Ryder Bibby) was hit on the port side in the engine room by one torpedo from U-107 about 250 miles southwest of the Cape Verde Islands. The ship had been in convoy OB-309, which was dispersed on 19 April in 50°00N/23°50W. Her engines stopped immediately and the ship sank by the stern after about 8 minutes. Two crew members on watch below were lost. One lifeboat had been destroyed by the explosion and another was damaged during launching, so the survivors had to be distributed between the two remaining boats, which lost contact to each other after 3 days. The master, second officer, 22 crew members and one lady passenger were picked up from their lifeboat on 9 May by the Benvrackie, which was herself sunk four days later by U-105 (Schewe). 15 survivors from Lassell were lost. The master, nine others and the survivors of Benvrackie were rescued after 13 days in lifeboats by the British hospital ship HMHS Oxfordshire and landed at Freetown. The chief officer H.W. Underhill, four officers, 13 crew members and eight gunners in the other lifeboat were picked up on 10 May in position 10°57N/29°13W by the British steam merchant Egba (Master G.D. Simpson, OBE) and landed at Freetown five days later.